I ended up with a different XO than the one pictured above - similar XO point, shallower null but flatter through the that region.
These will be at IowaDIY in October if anyone is interested in listening to them. I will reiterate my early impressions of the driver, but add that the breakup proved to problematic in this application. Fortunately, the breakup doesn't propagate as odd order distortion to any meaningful level, so the issues I was presented with dealt more with destructive summation in the treble region.
Anywhoo, some pictures...
Finished system. Drivers are flush mounted, and construction details (along with details of the previous project inhabiting this) are found here: http://techtalk.parts-express.com/showthread.php?239515-Un-named-MTM
On axis with individual driver responses:
A little distortion action:
On-axis over impedance:
Some horizontals, it is my opinion that the way this changes off-axis demonstrates how important it is to A: take horizontal measurements, and B: don't over-obsess with "filling in the blanks" - in this case the so-called BBC dip going on there.
Assembled crossovers. Coils wound down to within 1/2% of spec and caps selected to meet spec in appropriate series/parallel wiring configuration. I used my DerEE LCR meter to do the measuring.
I tried three different padding resistors - I am personally using the 6 ohm resistor. Since the tweeter covers such a large range (cuts in around 1150), the small differences in padding values have a bigger than typical impact on overall tonal balance.
Coils are both 18awg, with the woofer using a laminated core. For illustrative purposes, I showed the 5.5 hooked up but as stated, I am using the 6 ohm option. The caps are all common enough values, as are the coils.
Cabinet is approximately 0.6 cubic feet, with final tuning in the very low 50's. Impedance curve indicates a so-called "optimally" flat tuning. I used Black Hole 5 all over inside it - expect to do serious experimentation if you use that product. It eats up a lot more internal space than one might think. Worth it for the benefits it brings. If doing a more traditional cabinet construction, all four of my woofers measured within 10% of advertised (actually closer) so I would consider using supplied T/S adequate for modeling purposes.
All-in, using Solen caps is just over $400 - not a cheap project and right smack in the middle of a lot of serious contenders. However, the $400 does offer a couple of advantages such as the increased output potential of a 4 ohm MTM, and the low XO point makes it less objectionable for horizontal center channel use.
Great job on this driver, guys - keep 'em coming!!!